package knowlodges.JUCkuang.ProAndCon;

/**
 * 线程间的通信问题：生产者和消费者问题； 等待唤醒，通知唤醒
 * 线程交替执行  A  B操作同个变量  num=0
 * A num+1
 * B num-1
 */
public class ProducerAndConsumer {
    public static void main(String[] args) {
        Data data = new Data();
        new Thread(() -> {
            for (int i = 0; i < 10; i++) {
                try{
                    data.increment();
                } catch (InterruptedException e) {
                    throw new RuntimeException(e);
                }
            }
        }, "A").start();
        new Thread(() -> {
            for (int i = 0; i < 10; i++) {
                try{
                    data.decrement();
                } catch (InterruptedException e) {
                    throw new RuntimeException(e);
                }
            }
        }, "B").start();
        new Thread(() -> {
            for (int i = 0; i < 10; i++) {
                try{
                    data.increment();
                } catch (InterruptedException e) {
                    throw new RuntimeException(e);
                }
            }
        }, "C").start();
        new Thread(() -> {
            for (int i = 0; i < 10; i++) {
                try{
                    data.decrement();
                } catch (InterruptedException e) {
                    throw new RuntimeException(e);
                }
            }
        }, "D").start();
    }
}

//判断、等待、业务、通知
class Data {
    private int number = 0;

    //    +1
    public synchronized void increment() throws InterruptedException {
        while (number != 0) {
//            等待
            this.wait();
        }
        number++;
        System.out.println(Thread.currentThread().getName()+"=>"+number);
//        通知其他线程，我+1完毕了
        this.notifyAll();
    }

    //    -1
    public synchronized void decrement() throws InterruptedException {
        while (number == 0) {
//            等待
            this.wait();
        }
        number--;
        System.out.println(Thread.currentThread().getName()+"=>"+number);
//        通知其他线程，我-1完毕了
        this.notifyAll();
    }
}
